Confluent Developer ft. Tim Berglund, Adi Polak & Viktor Gamov Reimagining Stream Processing with Matthias J. Sax | Ep. 9
Nov 17, 2025
Matthias J. Sax, a senior software engineer at Confluent and stream processing expert, shares his intriguing career journey from an electrician trainee at BMW to a key figure in Kafka Streams. He discusses the technical challenges in API design and backward compatibility while building Kafka Streams as a library tailored for microservices. Matthias also dives into his PhD work on stream processing, the inspiration from Java Streams, and lessons learned from deprecations. Lastly, he offers valuable advice on deepening expertise in the field.
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From BMW Assembly Lines To Software
- Matthias started as an electrician trainee at BMW, working with robots, microelectronics, and some programming.
- That hands-on hardware experience later helped him understand how computers work and aided his transition to software and university.
Early Open Source Committer Journey
- Matthias contributed to Apache Flink and became a committer while doing his PhD work.
- He also worked on Apache Storm before joining Confluent to work on Kafka.
API Design Is A Long-Term Constraint
- API design and backward compatibility are core, ongoing challenges for library projects like Kafka Streams.
- Changing a widely used library must prioritize not breaking existing users and guiding correct usage.
